The invention relates to marine drive exhaust systems, and more particularly to interfacing seals therein preventing leakage of water and exhaust gas.
In a marine stern drive, for example a Mercury Marine Mercruiser 420, Parts Catalog 90-16286, 1987 , pages 16 and 17, an exhaust pipe is mounted to an exhaust elbow which in turn is mounted to an exhaust manifold, and each has a central passage surrounded by a plurality of peripheral water passages for cooling exhaust gas in the exhaust passage. The exhaust elbow inlet is bolted to the exhaust manifold at mating facing surfaces, with a gasket therebetween to seal same. The exhaust pipe is bolted to the exhaust elbow outlet at mating facing surfaces, with a gasket therebetween to seal same. Prior systems have experienced problems with leaking gaskets. Such leakage causes rust and corrosion of the parts, and is unsightly.
The present invention addresses and solves the noted leakage problem in a particularly simple and effective manner. A tight seal is provided between the noted facing surfaces. A shaped O-ring seal has an inner peripheral rib extending peripherally around the exhaust passage and generally conforming to the shape passage and the water passages. The shaped O-ring seal has an outer peripheral rib extending peripherally around the water passages and spaced laterally outward of the inner rib by a gap through which the water passages extend.